Object-oriented Software in Ada 95

Exceptions 167
11.1.1 Putting it all together
The package Interest_account and its child inspect_interest are used as follows:
with Ada.Text_Io, Ada.Float_Text_Io, Class_Account,
Class_Interest_Account, Class_Interest_Account.Inspect_Interest,
Statement;
use Ada.Text_Io, Ada.Float_Text_Io, Class_Account,
Class_Interest_Account, Class_Interest_Account.Inspect_Interest;
procedure Main is
My_Account: Interest_Account;
Obtained : Money;
begin
Statement( My_Account );
Put("Deposit 100.00 into account"); New_Line;
Deposit( My_Account, 100.00 ); --Day 1
Calc_Interest( My_Account ); --End of day 1
Calc_Interest( My_Account ); --End of day 2
Statement( My_Account ); --Day 3
Obtained := Interest_Is( My_Account ); --How much interest
Put("Interest accrued so far : £" );
Put( Obtained, Aft=>2, Exp=>0 ); New_Line;
end Main;
Note: When a child is included, its ancestors are automatically with’ed.
When run it will produce the following output:
Mini statement: The amount on deposit is £ 0.00
Deposit 100.00 into account
Mini statement: The amount on deposit is £100.00
Interest accrued so far : £ 0.05
11.1.2 Warning
A child package breaks the encapsulation rules of a package. In particular a child package can access the private
data components of its parent package. In accessing the private instance attributes of a class, the child package
may compromise the integrity of the parent package.
© M A Smith - May not be reproduced without permission